The present invention concerns an internal combustion engine and a method of operating such an internal combustion engine.
EP 359 298 A2 discloses an internal combustion engine having a main combustion chamber and pre-combustion chamber, in which the pre-combustion chamber is fed with a synthesis gas from a reformer. As the synthesis gas is hydrogen-bearing, the ignition characteristics of the internal combustion engine are improved thereby.
WO 2008/150370 A1 discloses an internal combustion engine with exhaust gas recycling, wherein the exhaust gas is reformed in terms of its substance together with a fuel in a reformer to give synthesis gas. That serves to reduce unwanted emissions in the exhaust gas of the internal combustion engine.
The use of both positive effects as described above is difficult as the optimum synthesis gas proportion in the fuel gas is different for the two effects, depending on the respective operating point of the internal combustion engine. In addition, the gas-engine utilization of synthesis gases is restricted due to self-ignition events depending on the gas composition (H2, CO, CH4, hydrocarbons having three or more carbon atoms as well as steam) and the mode of engine operation (power output, charge, . . . ) and due to knocking depending on the gas composition.